277
ACUS01 KWNS 230558
SWODY1
SPC AC 230556

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1256 AM CDT Thu May 23 2024

Valid 231200Z - 241200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN THE CENTRAL
GREAT PLAINS...

...SUMMARY...
Scattered severe thunderstorms are possible across the Great Plains
this afternoon into tonight, where a few tornadoes and isolated very
large hail are probable. The most likely concentration of severe
winds is expected across a portion of the central Great Plains this
evening into tonight. Some of these should be significant from 75-85
mph.

...Central to northern Great Plains...
The most synoptically evident region for severe storms is expected
downstream of a shortwave trough ejecting from the Northwest into
the northern Great Plains through 12Z Friday. A lee cyclone
initially between the Bighorns and Black Hills will track
east-northeast towards the Upper Red River Valley. A dryline/lee
trough will initially emerge eastward, before being progressively
overtaken from north to south by an accelerating cold front,
especially this evening into tonight.

With 60+ F surface dew points currently confined to the Ozarks and
the Upper Red River of the South, boundary-layer moisture quality
will be limited and spatially confined through this afternoon.
Nevertheless, pronounced surface heating, coupled with the favorable
large-scale forcing for ascent, will favor scattered thunderstorms
near the surface cyclone and adjacent warm front. Additional storms
will develop south along the surface trough/cold front. Deep-layer
shear will support several high-based supercells. Significant severe
hail and isolated severe gusts should be the primary early threat.

During the evening, most CAM guidance depicts upscale growth in the
central to eastern NE vicinity. This should be favored by a
strengthening low-level jet ahead of the increasingly convergent
cold front, and earlier supercells impinging on the more buoyant air
mass and broadening warm-moist sector advecting north. An
east-southeast moving QLCS with embedded bows may emerge towards the
Mid-MO Valley vicinity. This should yield potential for both
significant severe wind and brief tornadoes. Guidance spread
increases substantially with how long a severe MCS should persist
overnight.

...Southern Great Plains...
Outside of the dryline, large-scale ascent appears nebulous today.
Isolated to scattered morning convection may persist/redevelop to
the north of remnant outflow from central TX through the Mid-South.
Greater differential heating across this corridor may provide a
focus for sporadic thunderstorms downstream of the dryline. A belt
of enhanced mid-level westerlies should persist across north to
central TX through the afternoon. Large buoyancy with MLCAPE of
2500-3500 J/kg should  become common across OK through central TX
ahead of the dryline. Have maintained level 2-SLGT risk where either
residual outflow and dryline storms capable of all hazards appear
possible.

...TN Valley to the coastal New England/Mid-Atlantic States...
A broad swath of the eastern CONUS will have at least isolated
potential for strong to locally severe storms. Much of this area
will be characterized by weak to modest buoyancy (MLCAPE of 500-1500
J/kg) and moderate deep-layer, but weak low-level shear. Convective
enhancements will likely be tied to upstream MCVs, as well as along
corridors of greater morning to afternoon insolation. Have
maintained a large level 1-MRGL risk for both severe wind and hail.

..Grams/Barnes.. 05/23/2024

$$